In Glasgow two months ago a 14-year-old boy was jailed for seven years for fatally stabbing his 34-year-old foster mother. The incident took place a year ago. In the days leading up to the murder, the boy had been grounded, and his Xbox, mobile phone and laptop – which he used to keep in contact with his natural mother – were taken from him as punishment for his behaviour. According to his foster father, Bryan McKenzie, who had left the family home an hour before the attack, the boy didn't seem overly upset by the punishment. Dawn and Bryan McKenzie were first-time foster parents and were, perhaps, through no fault of their own, out of their depth with the boy. As seasoned fosterers/adopters are aware, there is a fine line when it comes to disciplining children who are already disturbed by their backgrounds, and taking so much from him was obviously inadvisable.

It's a story that constantly repeats itself – placing children with foster and adoptive families who cannot cope with their difficulties – though not often with fatal consequences. Either the social workers underplay the degree of a child's difficulties, or they don't understand the significance, and all too often, a ticking time-bomb is placed within innocent, well-meaning families.

In 2003, the Guardian published an account of my family's experiences of the adoption system. We had fostered Louise when she was two and a half, and adopted her five years later, still optimistic – despite the hell we had lived through already – that all would end up happily. In the early years, she smeared herself with excreta, picked wounds in herself until she bled, attacked anything that moved, and screamed day and night. We told social services that we would not knowingly take a child with learning disabilities because we didn't think we could cope, but we were told Louise was suffering from emotional deprivation, and all she needed was tender, loving care. Back then we were naive and didn't understand the rules. For instance, if we wouldn't "knowingly" take a child with learning disabilities, they just wouldn't tell us. What they also failed to pass on was that she had brain damage from having been battered and had a family history of mental illness.

Completely in the dark and too exhausted to do more than survive, we struggled on, trying to solve problems we didn't know existed, while caring for our other two children, one a year older than Louise, the other a year younger. The people at social services laughed when we wondered if Louise might have learning disabilities and by the time this became too apparent to deny, Louise was our child. That is what social services count on: if the child can be kept with you long enough, you will not want to give her/him up. It doesn't matter that other children in the family are being short-changed; their childhoods ruined while you try to cope with the one who needs the most attention and ends up with all of it. By the time Louise was 16, she was diagnosed with learning difficulties. She was suffering from brain damage, mental health problems and autism.

I wrote the 2003 article in response to a surge of adverts featuring celebrities encouraging people to adopt smiling, but needy, children. Tony Blair was in office, feverishly burnishing his public image by volunteering as patron saint and saviour of little children. Blair's father had been adopted, went the spiel, and it hadn't done him any harm, so we should get everyone adopted. Jane Asher also extolled the joys of adoption to the populace, despite not having any experience of adoption herself.

What has changed since 2003? Well, David Cameron has assumed the mantle of patron saint and saviour of little children, abetted by Michael Gove, who was himself adopted as a baby. What they are ignoring is that adoption has changed from what they think it ever was. For a start, there were never any well brought-up little orphans looking for loving parents. What we had were unmarried mothers who couldn't afford to raise children alone – though many did – and couldn't take the embarrassment and stigma of bearing an illegitimate child. But times have changed. Unmarried mothers are now single parents who have financial support from the state and there is no stigma these days – the "illegitimate" label that once marked children from cradle to grave has gone, and rightly so. What this means is that mothers are far more likely to keep their babies and there are virtually none available for adoption, so couples are encouraged to look at older children instead. And thereby a can of worms opens up.

According to the British Association for Adoption and Fostering, only 2% of the children adopted in the year to March 2011 in England were under one (71% were aged one to four, 24% five to nine). The children available for adoption these days have often been removed from parents who have mental health, drug and alcohol problems. They have most likely been left with those parents until the bitter end because the state believes that children do better with their own parents. By the time these children are removed, they are already damaged by years of neglect and abuse. They are no longer children in need of an ordinary family; in fact often that is the last thing they can cope with, and they are the last thing an ordinary family can cope with. In recent years, a few caveats have appeared in appeals. "Needs extra attention," is one. To prospective adopters, that seems reasonable. Until they've been put through the mill, they don't realise it actually means the life you had may be destroyed.

Local authorities don't own up to the breakdown rate in adoption either. Ask and the reply is very likely to be a vague "not much". Some local authorities and adoption agencies have been forced to admit to a rate of 20%, but that isn't the whole picture. Some years ago the Strathclyde region, then the biggest social work area in Europe, investigated the situation. That 1986 report found breakdown rates rising from 16% for children placed at age five, to 60% at nine and over – that's six out of 10 children adopted going back into care. And that report counted three years as a successful adoption, which doesn't take into account the fact breakdowns also happen later than that. The author of the report, Sandy Jamieson, former assistant director of social work in charge of childcare, reviewed the figures twice in the early 90s and found the situation had not improved, and indeed had possibly got worse. There is absolutely no reason to suspect that other areas of the UK have achieved better results.

But one thing that has changed since 2005 is that adopters are increasingly prepared to fight back. Social services are destroying marriages and lives, trying to get problem children off their books. It feels as though they will use any means, and that legal action against the local authorities concerned is the only thing that might stop them.

Chris and Jane are both officers in the Metropolitan police, and have four children, who were aged 25, 22, 12 and nine when the couple decided to adopt. Jane had worked in child protection for six years, and they had both been involved with the Scouts, the PTA and every other child-orientated organisation you can think of. They made the decision to adopt because they "wanted to make a difference". Five-and-a-half-year-old Suzie was presented to them by social services as "bright, bubbly, no shrinking violet, a perfect match for your family". Suzie's arrival, more than five years ago, was "an explosion". Jane describes a child who was scared of everything: "She would cower under her bed and was terrified of ordinary things. The TV scared her." Suzie's behaviour began to escalate into constant violence and aggression: "Every waking moment was chaos. It was like living in a war zone. Her school couldn't cope with her either.

"She seemed desperate to be loved, but couldn't take love, couldn't manage relationships at all. Other children didn't want to know her because of her behaviour, so she had no friends. She would scream at us constantly: 'I hate you! I hate this family! Send me back!' In fact her first words to us were: 'Are you going to be my forever mummy and daddy? Do you like hurting people?' We had expected emotional problems, but not the total destruction of our family."

At the same time, Jane and Chris were trying to cope with other problems. Their eldest son had a brain tumour and needed surgery, but Suzie was causing hell. "There was no help," Jane recalls. "We asked social services, but they did nothing. We were left to cope alone. Gradually we became isolated because other people don't want to put up with her."

Jane had a breakdown and still there was no support. Then came an incident in 2010 that still haunts her. "Suzie attacked me," she says. "She was screaming: 'Go on, punch me, you know you want to!' I wanted to annihilate her, I wanted to kill her and I didn't care if I was arrested. I raised my arm to hit her, but something stopped me. Even so, I couldn't go near her for two days. I called social services but once again they did nothing. I didn't adopt her to hate her or to harm her, but that's how it was."

On Mother's Day 2011, Jane had a second breakdown. "I just snapped. I got up, packed my bags and left," she remembers. "By now I was terrified of Suzie and just wanted to disappear for ever. I drove through the Highlands of Scotland for eight days, then boarded a ferry for the Isle of Lewis. I saw a police car and they flashed me. Chris had reported me missing. I didn't stop and there was a pursuit. It went on for over an hour – I even evaded roadblocks – and ended with them boxing me in, smashing the windows, dragging me out and handcuffing me. I was strip-searched and thrown into a cell for 21 hours. I wasn't even allowed to wash. When Chris arrived, he was allowed five minutes with me. I pleaded not guilty and the psychiatric reports confirmed I was ill from stress. In the end, I was given a complete discharge. Afterwards I was put on medication, but I still have panic attacks."

At the age of 11, Suzie is now registered as disabled because of her mental health problems and is also on medication, but her special school is still struggling with her, and with puberty fast approaching, her situation is certain to become more difficult. Chris and Jane felt so strongly about how they had been misled that they approached a solicitor to try to sue the local authority, but were advised by counsel that they wouldn't win because of a 2004 judgment of a similar case. In that instance the adoptive parents had won, only for the local authority to appeal. The judge allowed compensation, but only from placement to the time the couple found out what they had not been told about a boy's violent behaviour. Thereafter they kept the child instead of handing him back, and the judge decided they would not be compensated from the adoption date – they were effectively penalised for not abandoning the boy. The judgment stated: "If there is to be a duty of care, the professionals should be addressing their minds to their first consideration, the welfare of the child throughout his childhood, rather than anything else … we would not hold that it is fair, just or reasonable to impose on professionals involved in compiling reports for adoption agencies a duty of care towards prospective adopters."

Jane is angered by this, and by the judge's suggestion that "adopters have a trial period to decide whether to keep the child", as though children are defective used cars that you just return after a test drive. "In our case," says Jane, "when the papers were disclosed, you wouldn't believe the number they had 'lost'. We learned that the mother was a serious offender with mental health problems and there had been severe neglect for years. Suzie had been going into and out of care all her life and her difficulties had been known about. They just didn't tell us."

For Jane, the system is "appalling, soul-destroying and makes no sense. Where was their duty of care to Suzie when they placed her with a family without knowing if they could cope? She was severely let down by them. We were so low at one point, we talked about divorce. Where would it have left Suzie and our boys if that had happened?" The couple are investigating other legal avenues. They feel strongly that the legislation must be changed to ensure full disclosure of a child's difficulties, plus support after placement. "The only reason I go on is because I have to believe it will all be worth it. We have all suffered so much, I have to believe it wasn't for nothing."

Modern adoption is always difficult. Sometimes it brings happiness, and sometimes it ruins lives. Until something is done to sort a system that is clearly flawed and not fit for purpose, there needs to be an end to the call for faster universal adoption.